Sharepoint 2003 is limited when it comes to data recovery. In MOSS 2007 you now have a recylce bin to recover deleted items so this isn’t an issue here.
If you have deleted an item in SPS 2003 and it was contained in a SQL Backup then SPExplorer is your savyor. This tool interogates the SharePoint 2003 database directly and builts the site structure, then you can extra the document to your pc then upload back into sharepoint.